U.S. patent number 6,642,340 [Application Number 09/609,119] was granted by the patent office on 2003-11-04 for process for preparing an ethylene/.alpha.-olefin copolymer.
This patent grant is currently assigned to Mitsui Chemicals, Inc.. Invention is credited to Takasi Nakagawa, Masaaki Ohgizawa, Mamoru Takahashi.
United States Patent |
6,642,340 |
Takahashi , et al. |
November 4, 2003 |
Process for preparing an ethylene/.alpha.-olefin copolymer
Abstract
A process for preparing an ethylene/.alpha.-olefin copolymer,
which includes the steps of (A) copolymerizing ethylene and an
.alpha.-olefin of 3 to 20 carbon atoms by continuous vapor phase
polymerization; (B) copolymerization is conducted in the presence
of a prepolymerized catalyst obtained by prepolymerizing an olefin
in the presence of (a) a transition metal compound, (b) an
organoaluminum oxy-compound, (c) a fine particle carrier, and
optionally (d) an organoaluminum compound; and (C) copolymerization
is conducted under such condition that the partial pressure of sum
total of ethylene and .alpha.-olefin is 10 to 28 kg/cm.sup.2. The
resulting ethylene/.alpha.-olefin copolymer has the following
properties: (i) the density is in the range of 0.880 to 0.960
g/cm.sup.3, (ii) the melt flow rate of 190.degree. C. under a load
of 2.16 kg is in the range of 0.1 to 100 g/10 min, (iii) the melt
tension (MT (g)) at 190.degree. C. and the melt flow rate (MFR
(g/10 min)) satisfy the relation
MT.ltoreq.2.2.times.MFR.sup.-084.
Inventors: |
Takahashi; Mamoru (Waki-cho,
JP), Nakagawa; Takasi (Wako-cho, JP),
Ohgizawa; Masaaki (Waki-cho, JP) |
Assignee: |
Mitsui Chemicals, Inc. (Tokyo,
JP)
|
Family
ID: |
18366682 |
Appl.
No.: |
09/609,119 |
Filed: |
June 30, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
023717 |
Feb 13, 1998 |
|
|
|
|
771988 |
Dec 23, 1996 |
|
|
|
|
Foreign Application Priority Data
|
|
|
|
|
Dec 28, 1995 [JP] |
|
|
7-344104 |
|
Current U.S.
Class: |
526/348.2;
502/103; 502/104; 502/132; 502/152; 502/87; 526/124.1; 526/129;
526/160; 526/342; 526/348; 526/943 |
Current CPC
Class: |
C08F
210/16 (20130101); C08J 5/18 (20130101); C08F
210/16 (20130101); C08F 4/65916 (20130101); C08F
4/65912 (20130101); C08F 4/65916 (20130101); C08F
4/65922 (20130101); C08J 2323/08 (20130101); C08F
210/16 (20130101); C08F 210/14 (20130101); C08F
2500/11 (20130101); C08F 2500/12 (20130101); C08F
2500/26 (20130101); Y10S 526/943 (20130101) |
Current International
Class: |
C08F
210/16 (20060101); C08F 210/00 (20060101); C08J
5/18 (20060101); C08F 4/00 (20060101); C08F
4/6592 (20060101); C08F 4/659 (20060101); C08F
010/14 (); C08F 004/42 () |
Field of
Search: |
;526/160,943,129,348,342,124.1,348.2 ;502/103,132,152,104,87 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2162681 |
|
Nov 1994 |
|
CA |
|
2130502 |
|
Feb 1995 |
|
CA |
|
575123 |
|
Dec 1993 |
|
EP |
|
0605952 |
|
Jul 1994 |
|
EP |
|
6136060 |
|
May 1994 |
|
JP |
|
08-059746 |
|
May 1996 |
|
JP |
|
Other References
Database WPI, Section Ch, Week 9619, Derwent Publications Ltd.,
London, GB; & JP 08 059 746 A (Asahi Kasei Kogyo KK), Mar. 5,
1996..
|
Primary Examiner: Choi; Ling-Siu
Attorney, Agent or Firm: Burns, Doane, Swecker & Mathis,
LLP
Parent Case Text
This is a continuation of application Ser. No. 09/023,717 filed
Feb. 13, 1998 which is a division of application Ser. No.
08/771,988 filed Dec. 23, 1996, both of which are now abandoned,
application Ser. No. 09/023,717 is incorporated herein in its
entirety by reference thereto.
Claims
What is claimed is:
1. An ethylene/.alpha.-olefin copolymer which is a copolymer of
ethylene and 1-hexene and has the following properties: (i) the
density is in the range of 0.880 to 0.960 g/cm.sup.3, (ii) the melt
flow rate at 190.degree. C. under a load of 2.16 kg is in the range
of 0.1 to 100 g/10 min, (iii) the melt tension (MT (g)) at
190.degree. C. and the melt flow rate (MFR (g/20 min)) satisfy the
relation
in the case of MFR.ltoreq.10 g/10 min:
in the case of MFR.ltoreq.10 g/10 min:
and (vii) a component, which is eluted at a temperature of not
lower than 100.degree. C. in a temperature rise elution test
(TREF), exists in said copolymer, and the amount of the eluted
component is not more than 10% of the total amount of the
eluate.
2. A process for preparing an ethylene/.alpha.-olefin copolymer,
which comprises: (A) copolymerizing ethylene and 1-hexene by
continuous vapor phase polymerization; (B) copolymerization is
conducted in the presence of a prepolymerized catalyst obtained by
prepolymerizing ethylene in the presence of (a) a transition metal
metallocene compound catalyst, (b) an organoaluminum oxy-compound,
(c) a fine particle carrier, and optionally (d) an organoaluminum
compound; (C) copolymerization is conducted under such condition
that the partial pressure of the sum of the ethylene and 1-hexene
is 10 to 28 kg/cm.sup.2 ; and (D) the resulting ethylene/1-hexene
copolymer has the following properties: (i) the density is in the
range of 0.880 to 0.960 g/cm.sup.3, (ii) the melt flow rate of
190.degree. C. under a load of 2.16 kg is in the range of 0.1 to
100 g/10 min, (iii) the melt tension (MT (g)) at 190.degree. C. and
the melt flow rate (MFR (g/10 min)) satisfy the relation
in the case of MFR.ltoreq.10 g/10 min:
W<80.times.exp(-100(d-0.88))+0.1,
in the case of MFR>10 g/10 min:
(vi) the endotherm curve of said copolymer measured by a
differential scanning calorimeter has two or more peaks, and the
temperature (Tm.sub.1 (.degree. C.)) at the position of the peak on
the lowest temperature side, the temperature (Tm (.degree. C.)) at
the position of the maximum peak and the density (d (g/cm.sup.3))
satisfy the relation
and (vii) a component, which is eluted at a temperature of not
lower than 100.degree. C. in a temperature rise elution test
(TREF), exists in said copolymer, and the amount of the eluted
component is 0.5 to 8% of the total amount of the eluate.
3. The process as claimed in claim 2, wherein the resulting
ethylene/1-hexene copolymer has such properties that the copolymer
is capable of being case molded into a film having the following
properties: the film impact strength (FIS (J/m)) and the density (d
(g/cm.sup.3)) satisfy the relation
4. The process as claimed in claim 2, wherein the copolymerization
is conducted by a single stage vapor phase polymerization.
5. A film which is obtained from the ethylene/1-hexene copolymer
produced by the process as claimed in claim 2.
6. A cast film which is obtained by cast molding the
ethylene/1-hexene copolymer produced by the process as claimed in
claim 2 and has the following properties: the film impact strength
(FIS (J/m)) and the density (d (g/cm.sup.3)) satisfy the
relation
7. An ethylene/.alpha.-olefin copolymer which is prepared by
copolymerizing ethylene and 1-hexene in a single stage vapor
polymerization in the presence of a prepolymerized catalyst
obtained by prepolymerizing ethylene in the presence of (a) a
transition metal compound, (b) an aluminoxane compound, (c) a fine
solid particle carrier, and (d) a C.sub.1 -C.sub.4 alkylaluminum
compound, or a C.sub.1 -C.sub.4 alkylaluminum halide compound,
wherein said transition metal compound consists essentially of a
single metallocene catalyst of the formula (I):
in the case of MFR.ltoreq.10 g/10 min;
in the case of MFR>10 g/10 min:
W<80.times.(MFR-9).sup.0.26.times.exp(-100(d-0.88))+0.1, (v) the
temperature (Tm (.degree. C.)) at the position of the maximum peak
of an endotherm curve of said copolymer measured by a differential
scanning calorimeter and the density (d (g/cm.sup.3)) satisfy the
relation
and (vii) a component, which is eluted at a temperature of not
lower than 100.degree. C. in a temperature rise elution test
(TREF), exists in said copolymer, and the amount of the eluted
component is 1 to 5% by weight of the total amount of the
eluate.
8. The ethylene/1-hexene copolymer as claimed in claim 7, in which
in the ML.sub.x formula (I) the ligand L other than the
cyclopentadienyl group is hydrocarbon group of 1 to 3 carbon atoms
or a halogen atom.
9. The ethylene/1-hexene copolymer as claimed in claim 7, in which
the transition metal compound in the prepolymerized catalyst is a
member selected from the group consisting of bis(n-propyl
cyclopentadienyl)zirconium dichloride,
bis(n-butylcyclopentadienyl)zirconium dichloride,
bis(1-methyl-3-n-propylcyclopentadienyl)zirconium dichloride and
bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride.
10. The ethylene/1-hexene copolymer as claimed in claim 7, in which
the prepolymerization catalyst contains a C.sub.1 -C.sub.4
alkylaluminum compound.
11. The ethylene/1-hexene copolymer as claimed in claim 7, in which
the hexene is present in an amount of about 5.3% by weight and the
transition metal compound in the prepolymerized catalyst is
bis(1-methyl-3-n-butyl-cyclopentadienyl)zirconium dichloride.
12. The ethylene/1-hexene copolymer as claimed in claim 7, capable
of being cast molded into a film having the following properties:
the film impact strength (FIS (J/m) and the density (d
(g/cm.sup.3)) satisfy the relation
13. A film which is obtained from the ethylene/1-hexene copolymer
as claimed in claim 7.
14. A cast film which is obtained by cast molding the
ethylene/1-hexene copolymer as claimed in claim 7, and has the
following properties: the film impact strength (FIS (J/m)) and the
density (d(g/cm.sup.3)) satisfy the relation
15. The process for preparing the ethylene/.alpha.-olefin copolymer
of claim 2 wherein the copolymerizing of ethylene and 1-hexene is
carried out in a single stage vapor polymerization in the presence
of a prepolymerized catalyst obtained by prepolymerizing ethylene
in the presence of (a) a transition metal compound, (b) an
aluminoxane compound, (c) a fine solid particle carrier, and (d) a
C.sub.1 -C.sub.4 alkylaluminum compound, or a C.sub.1 -C.sub.4
alkylaluminum halide compound, wherein said transition metal
compound consists essentially of a single metallocene catalyst of
the formula (I):
16. The process of claim 15 wherein the ML.sub.x formula (I) the
ligand L other than the cyclopentadienyl group is hydrocarbon group
of 1 to 3 carbon atoms or a halogen atom.
17. The process of claim 15 wherein the transition metal compound
in the prepolymerized catalyst is a member selected from the group
consisting of bis(n-propyl cyclopentadienyl)zirconium dichloride,
bis(n-butylcyclopentadienyl)zirconium dichloride,
bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride.
18. The process of claim 15 wherein the prepolymerization catalyst
contains a C.sub.1 to C.sub.4 alkylaluminum compound.
19. The process of claim 15, wherein hexene is present in an amount
of about 5.3% by weight and the transition metal compound in the
prepolymerized catalyst is
bis(1-methyl-3-n-butyl-cyclopentadienyl)zirconium dichloride.
Description
FIELD OF THE INVENTION
The present invention relates to ethylene/.alpha.-olefin copolymers
and films obtained from the copolymers. More particularly, the
invention relates to ethylene/.alpha.-olefin copolymers having
excellent moldability, transparency and mechanical strength and
also relates to films obtained from the copolymers.
BACKGROUND OF THE INVENTION
Ethylene copolymers such as ethylene/.alpha.-olefin copolymers have
been molded by various molding methods, and they have been employed
in various fields. The ethylene copolymers are generally prepared
by the use of Ziegler catalysts.
In general, the ethylene polymers obtained by the use of titanium
catalysts among the Ziegler catalysts have excellent moldability
because of their wide molecular weight distribution and wide
composition distribution, but their molded products such as films
have a problem of surface tackiness.
Meanwhile, it is known that the ethylene polymers obtained by the
use of metallocene catalysts among the Ziegler catalysts generally
have narrow composition distribution and their molded products such
as films have an advantage of low surface tackiness. However,
because of narrow molecular weight distribution, these polymers are
inferior in the moldability to the ethylene polymers obtained by
the use of the titanium catalysts. In the prior art, therefore, the
ethylene polymers obtained by one use of the metallocene catalysts
have been blended with other polymers to improve the
moldability.
Under such circumstances as mentioned above, the present inventors
have earnestly studied. As a result, they have found that an
ethylene/.alpha.-olefin copolymer having the following properties
shows excellent moldability though this copolymer is obtained by
the use of a metallocene catalyst, and also found that this
copolymer has excellent film properties. That is, the
ethylene/.alpha.-olefin copolymer has the properties: the density
and the melt flow rate are each in the specific range; the melt
tension and the melt flow rate satisfy the specific relation; the
flow index and the melt flow rate satisfy the specific relation;
the quantity fraction of a decane-soluble component of the
copolymer and the density satisfy the specific relation; the
temperature at the position of the maximum peak of an endotherm
curve of the copolymer measured by a differential scanning a
calorimeter and the density satisfy the specific relation; the
endotherm curve of the copolymer measured by a differential
scanning calorimeter has two or more melting point peaks, and the
temperature at the position of the peak on the lowest temperature
side, the temperature at the position of the maximum peak and the
density satisfy the specific relation; and a component which is
eluted at a temperature or not lower than 100.degree. C. in a
temperature rise elution test (TREF) exists in the copolymer, and
the amount of the eluted component is in the specific range. Based
on the finding, the present invention has been accomplished.
OBJECT OF THE INVENTION
It is an object of the present invention to provide an
ethylene/.alpha.-olefin copolymer showing excellent moldability and
capable of producing molded products of excellent transparency and
mechanical strength and to provide a film obtained from the
copolymer.
SUMMARY OF THE INVENTION
The ethylene/.alpha.-olefin copolymer according to the invention is
a copolymer of ethylene and an .alpha.-olefin of 3 to 20 carbon
atoms and has the following properties; (i) the density is in the
range of 0.850 to 0.960 g/cm.sup.3, (ii) the melt flow rate at
190.degree. C. under a load of 2.16 kg is in the range of 0.1 to
100 g/10 min, (iii) the melt tension (MT (g)) at 190.degree. C. and
the melt flow rate (MFR (g/10 min)) satisfy the relation
in the case of MFR.ltoreq.10 g/10 min:
in the case of MFR>10 g/10 min:
and (vii) a component, which is eluted at a temperature of not
lower than 100.degree. C. in a temperature rising elution
fractionation test (TREF), exists in said copolymer, and the amount
of the eluted component is not more than 10% of the total amount of
the eluate.
When the ethylene/.alpha.-olefin copolymer is cast molded into a
film, the resulting film generally has the following properties:
the film impact strength: (FIS (J/m)) and the density (d
(g/cm.sup.3)) satisfy the relation
The ethylene/.alpha.-olefin copolymer of the invention has
excellent moldability, and from the copolymer, molded products
having excellent transparency and mechanical strength can be
obtained.
The film according to the invention is obtained from the
above-described ethylene/.alpha.-olefin copolymer.
The cast film according to the invention is obtained by cast
molding the ethylene/.alpha.-olefin copolymer and has the following
properties: the film impact strength (FIS (J/m)) and the density (d
(g/cm.sup.3)) satisfy the relation
The film of the invention is excellent not only in mechanical
strength, such as impact strength, tear strength and elastic
modulus, but also in transparency.
DETAILED DESCRIPTION OF THE INVENTION
The ethylene/.alpha.-olefin copolymer according to the invention
and the film obtained from the copolymer are described in detail
hereinafter.
The ethylene/.alpha.-olefin copolymer of the invention is a random
copolymer of ethylene and an .alpha.-olefin of 3 to 20 carbon
atoms.
In the ethylene/.alpha.-olefin copolymer, the constituent units
derived from ethylene are desirably contained in amounts of 65 to
99% by weight, preferably 70 to 98% by weight, more preferably 75
to 96% by weight, and the constituent units derived from the
.alpha.-olefin of 3 to 20 carbon atoms are desirably contained in
amounts of 1 to 35 % by weight, preferably 2 to 30% by weight, more
preferably 4 to 25% by weight.
Examples of the .alpha.-olefins of 3 to 20 carbon atoms include
propylene, 1-butene, 1-pentene, 1-hexane, 4-methyl-1-pentene,
1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,
1-octadecene and 1-eicosene.
The ethylene/.alpha.-olefin copolymer has a density of 0.880 to
0.960 g/cm.sup.3, preferably 0.885 to 0.940 g/cm.sup.3, more
preferably 0.890 to 0.935 g/cm.sup.3.
The ethylene/.alpha.-olefin copolymer has a melt flow rate, as
measured at 190.degree. C. under a load of 2.16 kg, of 0.1 to 100
g/10 min, preferably 0.3 to 50 g/10 min, more preferably 0.5 to 20
g/10 min.
In the ethylene/.alpha.-olefin copolymer, the melt tension (MT (g))
at 190.degree. C. and the melt flow rate (MFR (g/10 min)) satisfy
the relation
In the ethylene/.alpha.-olefin copolymer, further, the quantity
fraction (W (% by weight)) of its n-decane-soluble component at
23.degree. C. and the density (d (g/cm.sup.3)) satisfy the relation
in the case of MFR.ltoreq.10 g/10 min:
It can be said that the ethylene/.alpha.-olefin copolymer having
the above properties shows a narrow composition distribution.
In the ethylene/(.alpha.-olefin copolymer, the temperature (Tm
(.degree. C.)) at the position of the maximum peak of its endotherm
curve measured by a differential scanning calorimeter and the
density (d (g/cm.sup.3)) satisfy the relation
Because of low Tm for its density, the ethylene/.alpha.-olefin
copolymer shows better heat sealability as compared with an
ethylene/.alpha.-olefin copolymer having the same density.
In the endotherm curve of the ethylene/.alpha.-olefin copolymer
measured by a differential scanning calorimeter (DSC), there are
two or more peaks, and the temperature (Tm.sub.1 (.degree. C.)) at
the position of the peak on the lowest temperature side, the
temperature (Tm (.degree. C.)) at the position of the maximum peak
and the density (d (g/cm.sup.3)) satisfy the relation
The ethylens/.alpha.-olefin copolymer, which has such properties
that is endotherm curve measured by DSC has two or more peaks and
that the temperature (Tm.sub.1 (.degree. C.)) at the position of
the peak on the lowest temperature side, the temperature (Tm
(.degree. C.)) at the position of the maximum peak and the density
(d (g/cm.sup.3)) satisfy the above relation, shows a low starting
temperature of heat sealing and good hot tack when it is molded
into a film.
In the ethylene/.alpha.-olefin copolymer, a component which is
eluted at a temperature or not lower than 100.degree. C. in a
temperature rising elution fractionation test (TREF) exists, and
the amount of the eluted component is not more than 10%, preferably
0.5 to 8%, more preferably 1 to 5%, of the total amount of the
eluate.
From the ethylene/.alpha.-olefin copolymer wherein a component
which is eluted at a temperature of not lower than 100.degree. C.
in the measurement or TREF exists and the amount of said component
is in the above range, a film having excellent tear strength, high
elastic modulus and high nerve can be obtained.
When the ethylene/.alpha.-olefin copolymer is cast molded into a
film, the resulting film generally has the following properties:
the film impact strength (FIS (J/m)) and the density (d
(g/cm.sup.2)) satisfy the relation
The ethylene/.alpha.-olefin copolymer can be prepared by, for
example, copolymerizing ethylene and an .alpha.-olefin of 3 to 20
carbon atoms in a gas phase under the later-described specific
condition in the presence of an olefin polymerization catalyst
formed from: (a) the later-described transition metal compound, (b)
an organoaluminum oxy-compound, (c) a fine particle carrier,
and optionally (d) an organoaluminum compound, in such a manner
that the resulting copolymer has a density of 0.880 to 0.960
g/cm.sup.3.
The olefin polymerization catalyst and the catalyst components are
described below.
The transition metal compound (a) (sometimes referred to as
"component (a)" hereinafter) used for preparing the
ethylene/.alpha.-olefin copolymer is a transition metal compound
represented by the following formula (I).
In the formula (I), M is a transition metal atom selected from
Group IVB of the periodic table, specifically, zirconium, titanium
or hafnium, preferably zirconium.
x is a valence of the transition metal atom M and represents the
number of L coordinated to the transition metal atom.
L is a ligand coordinated to the transition metal atom M, and at
least two of the ligands L are each a cyclopentadienyl group, a
methylcyclopentadienyl group, an ethylcyclopentadienyl group or a
substituted cylcopentadienyl group having at least one substituent
selected from hydrocarbon groups of 3 to 10 carbon atoms. The
ligand L other than the (substituted) cyclopentadienyl group is a
hydrocarbon group of 1 to 12 carbon atoms, an alkoxy group, an
aryloxy group, a halogen atom, a trialkylsilyl group or a hydrogen
atom.
The substituted cyclopentadienyl group may have two or more
substituents, and the two or more substituents may be the same or
different from each other. When the substituted cyclopentadienyl
group hare two or more substituents, at least one substituent is a
hydrocarbon group of 3 to 10 carbon atoms, and other substituents
may be each methyl, ethyl or a hydrocarbon group of 3 to 10 carbon
atoms. The substituted cyclopentadienyl groups coordinated to M may
be the same as or different from each other.
Examples of the hydrocarbon groups of 3 to 10 carbon atoms include
alkyl groups, cycloalkyl groups, aryl groups and aralkyl groups.
More specifically, there can be mentioned alkyl groups, such as
n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl,
hexyl, octyl-2-ethylhexyl and decyl; cycloalkyl groups, such as
cyclopentyl and cyclohexyl; aryl groups, such as phenyl and tolyl;
and aralkyl groups, such as benzyl and neophyl.
Of these, preferable are alkyl groups, and particularly preferable
are n-propyl and n-butyl.
In the present invention, the (substituted) cyclopentadienyl group
coordinated to the transition metal is preferably a substituted
cyclopentadienyl group, more preferably a cyclopentadienyl group
substituted with an alkyl group of 3 or more carbon atoms, still
more preferably a di-substituted cyclopentadienyl group,
particularly preferably a 1,3-substituted cyclopentadienyl
group.
In the formula (I), the ligand L other than the (substituted)
cyclopentadienyl group coordinated to the transition metal atom M
is a hydrocarbon group of 1 to 12 carbon atoms, an alkoxy group, an
aryloxy group, a halogen atom, a trialkylsilyl group or a hydrogen
atom.
Examples of the hydrocarbon groups of 1 to 12 carbon atoms include
alkyl groups, cycloalkyl groups, aryl groups and aralkyl groups.
More specifically, there can be mentioned alkyl groups, such as
methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,
t-butyl, pentyl, hexyl, octyl, 2-ethylhexyl and decyl; cycloalkyl
groups, such as cyclopentyl and cyclohexyl; aryl groups, such as
phenyl and tolyl; and aralkyl groups, such as benzyl and
neophyl.
Examples of the alkoxy groups include methoxy, ethoxy, n-propoxy,
isopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butoxy, pentoxy,
hexoxy and octoxy.
Examples of the aryloxy groups include phenoxy.
Examples of the halogen atoms include fluorine, chlorine, bromine
and iodine.
Examples of the trialkylsilyl groups include trimethylsilyl,
triethylsilyl and triphenylsilyl.
Listed below are examples of the transition metal compounds
represented by the formula (I). Bis(cyclopentadienyl)zirconium
dichloride, Bis(methylcyclopentadienyl)zirconium dichloride,
Bis(ethylcyclopentadienyl)zirconium dichloride,
Bis(n-propylcyclopentadienyl)zirconium dichloride,
Bis(n-butylcyclopentadienyl)zirconium dichloride,
Bis(n-hexylcyclopentadienyl)zirconium dichloride,
Bis(methyl-n-propylcyclopentadienyl)zirconium dichloride,
Bis(methyl-n-butylcyclopentadienyl)zirconium
Bis(dimethyl-n-butylcyclopentadienyl)zirconium dichloride,
Bis(n-butylcyclopentadienyl)zirconium dibromide,
Bis(n-butylcyclopentadienyl)zirconium methoxychloride,
Bis(n-butylcyclopentadienyl)zirconium ethoxychloride,
Bis(n-butylcyclopentadienyl)zirconium butoxychloride
Bis(n-butylcyclopentadienyl)zirconium ethomide,
Bis(n-butylcyclopentadienyl)zirconium methylchloride,
Bis(n-butylcyclopentadienyl)zirconium dimethyl,
Bis(n-butylcyclopentadienyl)zirconium benzylchloride
Bis(n-butylcyclopentadienyl)zirconium dibenzyl,
Bis(n-butylcyclopentadienyl)zirconium phenylchloride, and
Bis(n-butylcyclopentadienyl)zirconium hydride chloride.
In the above examples, the di-substituted cyclopentadienyl rings
include 1,2-substituted cyclopentadienyl rings and 1,3-substituted
cyclopentadienyl rings. The tri-substituted cyclopentadienyl rings
include 1,2,3-substituted cylcopentadienyl rings and
1,2,4-substituted cyclopentadienyl rings. In the present invention,
also employable are transition metal compounds wherein zirconium is
replaced with titanium or hafnium in the above-exemplified
zirconium compounds.
Of the above transition metal compounds, particularly preferable
are: bis(n-propylcyclopentadienyl)zirconium dichloride,
bis(n-butylcyclopentadienyl)zirconium dichloride,
bis(1-methyl-3-n-propylcyclopentadienyl)zirconium dichloride, and
bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride.
The organoaluminum oxy-compound (b) (sometimes referred to as
"component (b) " hereinafter) may be a benzene-soluble aluminoxane
conventionally known or a benzene-insoluble organoaluminum
oxy-compound disclosed in Japanese Patent Laid-Open Publication No.
276807/1990.
The conventionally known aluminoxane can be prepared, for example,
by contacting the later-described organoaluminum compound with
water such as adsorbed water, water of crystallization, ice or
water vapor, or by causing the later-described organoaluminum
compound to react with organotin oxide.
The fine particle carrier (c) used in the invention is an inorganic
or organic, granulated or articulate solid compound having a
particle diameter of 10 to 300 .mu.m preferably 20 to 200 .mu.m. As
the inorganic carrier, porous inorganic oxide is preferably
employed. Examples of such oxides include SiO.sub.2, Al.sub.2
O.sub.3, MgO, Zr.sub.2, TiO.sub.2, B.sub.2 O.sub.3, CaO, ZnO, BaO,
ThO.sub.2 and mixtures thereof such as SiO.sub.2 --MgO, SiO.sub.2
--Al.sub.2 O.sub.3, SiO.sub.2 --TiO.sub.2, SiO.sub.2 --V.sub.2
O.sub.5, SiO.sub.2 --Cr.sub.2 O.sub.3 andSiO.sub.2 --TiO.sub.2
--MgO. Among them, preferable are those containing SiO.sub.2 and/or
Al.sub.2 O.sub.3 astheir major component.
The above-mentioned inorganic oxides may contain small amounts of
carbonate component, sulfate component, nitrate component and oxide
component, such as Na.sub.2 CO.sub.3, K.sub.2 CO.sub.3, CaCO.sub.3,
MgCO.sub.3, Na.sub.2 SO.sub.4, Al.sub.2 l (SO.sub.4).sub.3,
BaSO.sub.4, KNO.sub.3, Mg(NO.sub.3).sub.2, Al(NO.sub.3).sub.3,
Na.sub.2 O, K.sub.2 O and Li.sub.2 O.
The properties of the fine particle carrier (c) vary depending on
the type of the carrier and the process for the preparation
thereof, but preferably used is a fine particle carrier having a
specific surface area of 50 to 1,000 m.sup.2 /g, preferably 100 to
700 m.sup.2 /g, and a pore volume of 0.3 to 2.5 cm.sup.3 /g. The
fine particle carrier may be used after calcined at a temperature
of 100 to 1,000.degree. C., preferably 150 to 700.degree. C., if
desired.
Also employable as the fine particle carrier is an organic,
granular or particulate solid compound having a particle diameter
of 10 to 300 .mu.m. For example, (co)polymers produced mainly from
.alpha.olefins of 2 to 14 carbon atoms such as ethylene, propylene,
1-butene and 4-methyl-1-pentene or (co)polymers produced mainly
from vinylcyclohexane or styrene are employable.
The olefin polymerization catalyst used for preparing the
ethylene/.alpha.-olefin copolymer is formed from the component (a),
the component (b) and the component (c). In addition thereto, an
organoaluminum compound (d) may be used, if necessary.
The organoaluminum compound (d) (sometimes referred to as
"component (d)" hereinafter) is, for example, a compound
represented by the following formula (II):
wherein R.sup.1 is a hydrocarbon group of 1 to 12 carbon atoms, X
is a halogen atom or a hydrogen atom, and n is 1 to 3.
In the formula (II), R.sup.1 is a hydrocarbon group of 1 to 12
carbon atoms, e.g., an alkyl group, a cycloalkyl group or an aryl
group. Particular examples of those groups include methyl, ethyl,
n-propyl, isopropyl, isobutyl, pentyl, hexyl, octyl, cyclopentyl,
cyclohexyl, phenyl and tolyl.
Examples of such organoaluminum compounds include:
trialkylaluminums, such as trimethylaluminum, triethylaluminum,
triisopropylaluminum, triisobutylaluminum, trioctylaluminum and
tri-2-ethylhexylaluminum; alkenylaluminums, such as
isoprenylaluminum; dialkylaluminum halides, such as
dimethylaluminum chloride, diethylaluminum chloride,
diisopropylaluminum chloride, diisobutylaluminum chloride and
dimethylaluminum bromide; alkylaluminum sesquihalides, such as
methylaluminum sesquichloride, ethylaluminum sesquichloride,
isopropylaluminum sesquichloride, butylaluminum sesquichloride and
ethylaluminum sesquibromide; alkylaluminum dihalides, such as
methylaluminum dichloride, ethylaluminum dichloride,
isopropylaluminum dichloride and ethylaluminum dibromide; and
alkylaluminum hydrides, such as diethylaluminum hydride and
diisobutylaluminum hydride.
Also employable as the organoaluminum compound (d) is a compound
represented by the following formula (III):
wherein R.sup.1 is the same hydrocarbon as described for R.sup.1 in
the formula (II); Y is --OR.sup.2 group, --OSiR.sup.3.sub.3 group,
--OAlR.sup.4.sub.2 group, --NR.sup.5.sub.2 group, --SiR.sup.6.sub.3
group or --N(R)AlR.sup.8.sub.2 group; n is 1 to 2; R.sup.2,
R.sup.3, R.sup.4 and R.sup.8 are each methyl, ethyl, isopropyl,
isobutyl, cyclohexyl, phenyl or the like; R.sup.5 is hydrogen,
methyl, ethyl, isoprozyl, phenyl, trimethylsilyl or the like; and
R.sup.6 and R.sup.7 are each methyl, ethyl or the like.
Of such organoaluminum compounds, preferable are compounds of the
formula R.sup.1.sub.n Al(OAlR.sup.4.sub.2).sub.3-n, e.g., Et.sub.2
AlOAlEt.sub.2 and (iso-Bu).sub.2 AlOAl(iso-Bu).sub.2.
Of the organoaluminum compounds represented by the formulas (II)
and (III), preferable are compounds of the formula R.sup.1.sub.3
Al, and particularly preferable are compounds of the same formula
wherein R.sup.1 is an isoalkyl group.
In the preparation of the ethylene/.alpha.-olefin copolymer, the
catalyst prepared by contacting the component (a), the component
(b), the fine particle carrier (c), and if necessary, the component
(d) is employed.
The contact of the above components is carried out in an inert
hydrocarbon solvent. Examples of the inert hydrocarbon solvents
used for preparing the catalyst include aliphatic hydrocarbons,
such as propane, butane, pentane, hexane, heptane, octane, decane,
dodecane and kerosine; alicyclic hydrocarbons, such as
cyclopentane, cyclohexane and methylcylcopentane; aromatic
hydrocarbons, such as benzene, toluene and xylene; halogenated
hydrocarbons, such as ethylene chloride, chlorobenzene and
dichloromethane; and mixtures of these hydrocarbons.
The catalyst used for preparing the ethylene/.alpha.-olefin
copolymer may be a prepolymerized catalyst obtained by
prepolymerizing an olefin in the presence of the component (a), the
component (b), the fine particle carrier (c), and if necessary, the
component (d). The prepolymerization can be carried out by
introducing an olefin into an inert hydrocarbon solvent in the
presence of the component (a) the component (b), the fine particle
carrier (c), and if necessary, the component (d).
Examples of the olefins used in the prepolymerization include
ethylene and the same .alpha.-olefins of 3 to 20 carbon atoms as
described above. Of these, particularly preferable is ethylene of a
combination of ethylene and an .alpha.-olefin, which is used in the
polymerization.
The prepolymerization can be carried out by any of batchwise and
continuous processes, and it can be carried out under reduced
pressure, atmospheric pressure or application of pressure. In the
prepolymerization, it is desired that a prepolymer having an
intrinsic viscosity [.eta.], as measured in decalin at 135.degree.
C., of 0.2 to 7 dl/g, preferably 0.5 to 5 dl/g, is produced by
allowing hydrogen to coexist in the system.
The ethylene/.alpha.-olefin copolymer is obtained by copolymerizing
ethylene and the same .alpha.-olefin of 3 to 2 carbon atoms as
described above in a gas phase in the presence of the olefin
polymerization catalyst or the prepolymerized catalyst.
In the polymerization, the olefin polymerization catalyst or the
prepolymerized catalyst is desirably used in such an amount that
the concentration of the transition metal atom in the
polymerization reaction system is usually 10.sup.-8 to 10.sup.-3
g.multidot.atom/liter, preferably 10.sup.-7 to 10.sup.-4
g.multidot.atom/liter.
In the polymerization, an organoaluminum oxy-compound similar to
the component (b) and/or the organoaluminum compound (d) may be
added. In this case, the atomic ratio of aluminum atom (Al) derived
from the organoaluminum oxy-compound and the organoaluminum
compound to the transition metal atom (m) derived from the
transition metal compound (a), Al/M, is in the range of 5 to 300,
preferably 10 to 200, more preferably 15 to 150.
The polymerization temperature is in the range of usually 0 to
120.degree. C., preferably 20 to 100.degree. C.
The polymerization pressure is n the range or usually atmospheric
pressure to 100 kg/cm.sup.2, preferably 2 to 50 kg/cm.sup.2. The
polymerization can be carried out by any of batchwise,
semi-continuous and continuous processes.
At this time, the partial pressure of the monomers is desirably in
the range of 8 to 41 kg/cm.sup.2, preferably 10 to 28 kg/cm.sup.2.
Moreover, the partial pressure of the monomer is desirably 40 to
90% of total pressure, preferably 50 to 80%.
Adopting the aforementioned conditions, catalytic activity is
increased and the size of polymer particle in the fluidizing bed is
enlarged, thereby reducing the formation of fine particulate
polymers and the amount of ungrown catalyst particles. Accordingly,
fouling and sheeting in the reactor are prevented. Moreover,
invasion of fine particulate polymers and/or catalyst into the
circular gas-line is prevented, thereby preventing the choking of
circular gas-line, heat-exchanger, gas dispersing plate and the
like.
Furthermore, polymer components having high conductivity are
produced in large amount, thereby preventing the generation of
static electricity. Still more, flowability of the polymer
particles in the fludizing bed is improved, and thereby preventing
the sheeting and the formation of bulky polymer.
Under such conditions as described above, the
ethylene/.alpha.-copolymer according to the present invention can
be prepared by single stage vapor phase polymerization.
Accordingly, the preferred process for preparing the
ethylene/.alpha.-olefin copolymer of the present invention is the
single stage vapor phase polymerization using the aforementioned
prepolymerized catalyst.
Further, the polymerization may be conducted in two or more stages
under different reaction conditions.
To the ethylene/.alpha.-olefin copolymer of the invention, various
additives, such as weathering stabilizer, heat stabilizer,
antistatic agent, anti-slip agent, anti-blocking agent,
anti-fogging agent, lubricant, pigment, dye, nucleating agent,
plasticizer, anti-aging agent, hydrochloric acid absorbent and
antioxidant, may be added within limits not prejudicial to the
object of the invention.
The ethylene/.alpha.-olefin copolymer or the invention can be used
without any specific limitation in fields where ethylene copolymers
have been conventionally used, and it can be particularly suitably
used for films such as cast film and inflation film or sheets such
as extrusion sheet.
For producing films or sheets from the ethylene/.alpha.-olefin
copolymer of the invention, conventional methods and conditions can
be adopted.
In the cast film obtained from the ethylene/.alpha.-olefin
copolymer of the invention, it is desired that the film impact
strength (FIS (J/m)) and the density (d (g/cm.sup.3)) satisfy the
relation
The cast film obtained from the ethylene/.alpha.-olefin copolymer
of the invention is excellent in not only optical properties such
as haze and gloss but also in mechanical strength such as elastic
modulus, elongation, impact strength and tear strength. Besides,
the cast film has excellent blocking resistance and a low
coefficient of friction.
EFFECT OF THE INVENTION
The ethylene/.alpha.-olefin copolymer of the invention shows
excellent moldability, and from this copolymer, molded products
having excellent mechanical strength and transparency can be
obtained.
When the ethylene/.alpha.-olefin copolymer of the invention is
molded into a film such as a cast film, the resulting film shows
excellent transparency and mechanical strength.
Described below are definitions of property values, measurement of
property values and a molding method used herein.
(1) Granulation of Ethylene Copolymer
100 parts by weight of a powdery ethylene copolymer obtained by a
gas phase polymerization process is blended with 0.05 part by
weight of tri(2,4-di-t-butylphenyl)phosphate as a secondary
antioxidant, 0.1 part by weight of
n-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate as a
heat stabilizer and 0.05 part by weight of calcium stearate as a
hydrochloric acid absorbent. Then, the blend is melt extruded by a
twin-screw conical-tapered extruder (manufactured by Harquenton at
a preset temperature of 180.degree. C., to prepare granular
pellets.
(2) Density
Strands obtained in the measurement of melt flow rate at
190.degree. C. under a load of 2.16 kg are heat treated at
120.degree. C. for 1 hour and slowly cooled to room temperature
over a period of 1 hour. Then, the density is measured by a
gradient density tube.
(3) Composition of Copolymer
Composition of a copolymer is determined by .sup.13 C-NMR. That is,
a .sup.13 C-NMR spectrum of a sample obtained by homogeneously
dissolving about 200 mg of a copolymer powder in 1 ml of
hexachlorobutadiene in a sample tube having a diameter of 10 mm is
measured under the measuring conditions of a measuring temperature
of 120.degree. C., a measuring frequency of 25.05 MHz, a spectrum
width of 1,500 Hz, a pulse repetition time of 4.2 sec and a pulse
width of 6 .mu.sec.
(4) Melt Flow Rate (MFR)
The melt flow rate is measured using granular pellets of a
copolymer in accordance with ASTM D 1238-65T under the conditions
of a temperature of 190.degree. C. and a load of 2.16 kg.
(5) Measurement of Temperature (Tm.sub.1, Tm) at Peak Position by
DSC
An apparatus of DSC-7 model manufactured by Perkin Elmer Co. was
used. The temperatures (Tm.sub.1, Tm) at the positions of an
endotherm curve were found from an endotherm curve which is
obtained by heating a sample of about 5 mg up to 200.degree. C. at
a rate of 10.degree. C./min in an aluminum pan, maintaining the
sample at 200.degree. C. for 5 minutes, cooling it to room
temperature at a rate of 10.degree. C./min and heating it at a rate
of 10.degree. C./min.
(6) Quantity Fraction (W) of n-Decane-soluble Component
The quantity fraction (W) of a n-decane-soluble component is
measured in the following manner. About 3 g of a copolymer is added
to 450 ml of n-decane, dissolved therein at 145.degree. C. and
cooled to 23.degree. C. The n-decane-insoluble portion is removed
by filtration, and the n-decane-soluble portion is recovered from
the filtrate.
The quantity fraction (W) of a n-decane-soluble component is
defined by the following formula:
A copolymer having a small quantity fraction of soluble component
has a narrow composition distribution.
(7) Melt Tension (MT)
The melt tension is determined by measuring a stress given when a
molten polymer is stretched at a constant rate. That is, granular
pellets of a copolymer are used as a sample to be measured, and the
measurement is carried out using a MT measuring machine
(manufacture by Toyo Seiki Seisakusho) under the conditions of a
resin temperature of 190.degree. C., an extrusion speed of 15
mm/min, a take-up rate of 10 to 20 m/min, a nozzle diameter of 2.09
mm and a nozzle length of 8 mm.
(8) Flow Index (FI)
The flow index is determined by extruding a resin through a
capillary with varying a shear rate and finding a shear rate
corresponding to the prescribed stress. That is, using the same
sample as in the measurement of MT, the flow index is measured by a
capillary flow tester (manufactured by Toyo Seiki Seisakusho K.K.)
under the conditions of a resin temperature of 190.degree. C. and a
shear stress of about 5.times.10.sup.-4 to 3.times.10.sup.-6
dyne/cm.sup.2.
In this measurement, the diameter of a nozzle (capillary) is varied
according to MFR (g/10 min) of the resin, as described below.
MFR>20: 0.5 mm 20.gtoreq.MFR>3: 1.0 mm 3.gtoreq.MFR>0.8;
2.0 mm 0.8.gtoreq.MFR: 3.0 mm
(9) Temperature Rising Elution Fractionation Test (TREF)
A sample solution was introduced into a column at 140.degree. C/,
then cooled to 25.degree. C. at a cooling rate of 10.degree. C./hr,
and heated at a heating rate of 15.degree. C./hr to the temperature
at which the amount of eluate is not substantially increased.
During this process, a component continuously eluted at a constant
flow rate of 1.0 ml/min was detected by the online system, the
detector of which is Magna 550 type FTIR (Nicolet Co.)
In this test, a column of 2.14 cm (diameter).times.15 cm was used,
glass beads 100 .mu.m in diameter were used as a filler, and
orthochlorobenzene was used as a solvent. The concentration of the
sample solution was 200 mg/40 ml-orthochlorobenzene, and the
quantity of the sample solution was 7.5 ml.
(10) Production of Film
A film having a thickness of 40 .mu.m was produced by cast molding
using a single-screw extruder (diameter: 30 mm, L/D: 25) under the
conditions of a lip width of 0.7 mm, a processing temperature of
210.degree. C., an extrusion quantity of about 22 g, a roll
temperature of 40.degree. C. and a take-up rate of 2.4 m/min.
(11) Evaluation of Film Properties
(a) Haze
The haze was measured in accordance with ASM D 1003-61.
(b) Gloss
The gloss was measured in accordance with JIS Z 8741.
(c) Film Impact Strength (FIS)
The film impact strength was measured by a pendulum type film
impact tester manufactured by Toyo Seiki Seisakusho.
(d) Complete Heat-sealing Temperature
Heat sealing was carried out using a heat sealer manufactured by
Tester Industry. That is, a film was cut to have a size of about
120 mm.times.120 mm (a set of two sheets). Two of the films thus
cut were heat sealed at side with a sealing width of 5 mm under a
sealing press of 2 kg/cm.sup.2 for a sealing period of 1 second.
The press temperature of the sealing bar was varied by 5.degree.
C., and at each temperature the films were heat sealed.
The films thus heat sealed were cut perpendicularly to the heat
sealed portion to give a specimen of 15 mm (width).times.100 mm.
The two sides on the side opposite to the heat sealed portion of
the specimen were chucked by an air chuck of an Instron type
universal tester, and a tensile test was carried out under the
conditions of a chuck distance of 15 mm and a pulling rate of 300
mm/min. The lowest temperature at which the heat sealed portion was
not separated and a part of the substrate was broken was regarded
as the complete heat-sealing temperature.
(e) Elmendorf Tear Strength
The Elmendorf tear strength was measured in accordance with JIS Z
1702 using an Elmendorf tear tester manufactured by Toyo Seiki
Seisakusho. A notch was given in each of the film take-up direction
(MD) and the direction (TD) perpendicular to the film take-up
direction.
(f) Elastic Modulus
From the film, a dumbbell specimen having a size based on JIS K
6713 was punched out. The specimen was punched out in each of the
film take-up direction (MD) and the direction (TD) perpendicular to
the film take-up direction.
The specimen was chucked by an air chuck of an Instron type
universal tester, and a tensile test was carried out under the
conditions of a chuck distance of 86 mm and a pulling rate of 200
mm/min. A tilt against the displacement of the initial stress was
regarded as the elastic modulus.
(g) Blocking Force
An inflation film having a size of 10 cm.times.20 cm was sandwiched
between two sheets of typing paper, then further sandwiched between
two glass plates, and thereto was applied a load of 10 kg in an air
bath at 50.degree. C. for 24 hours. Then, the film was separated
from the typing paper by means of an open-type tool at a rate of
200 mm/min. A load applied to separate the film was taken as A (g),
and the blocking force (F (g/cm)) was calculated by the
equation:
EXAMPLE
The present invention will be further described with reference to
the following examples, but it should be construed that the
invention is in no way limited to those examples.
Preparation Example 1
Preparation of Ethylene/.alpha.-olefin Copolymer [A]
Preparation of Catalyst
Silica of 10 kg having been dried at 250.degree. C. for 10 hours
was suspended in 154 liters of toluene, and the resulting
suspension was cooled to 0.degree. C. Then, to the suspension was
dropwise added 57.5 liters of a toluene solution of
methylaluminoxane (Al: 1.33 ml/liter) over period of 1 hour. During
the addition, the temperature of the system was maintained at
0.degree. C. Subsequently, the reaction was conducted at 0.degree.
C. for 30 minutes. Then, the temperature of the system was raised
to 95.degree. C., over a period of time 1.5 hours, and at this
temperature the reaction was conducted for 20 hours. Thereafter,
the system was cooled to 60.degree. C., and the supernatant liquid
was removed by decantation. The resulting solid component was
washed twice with toluene and resuspended in 100 liters of toluene.
To the system, 16.8 liters of a toluene solution of
bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride (Zr:
27.0 mmol/l) was dropwise added at 80.degree. C. over a period or
30 minutes. The reaction was further conducted at 80.degree. C. for
2 hours. Then, the supernatant liquid was removed, and the
remainder was washed twice with hexane to obtain a solid catalyst
containing 3.5 mg of zirconium per 1 g of the catalyst.
Preparation of Prepolymerized Catalyst
To 87 liters of hexane containing 2.5 mol of triisobutylaluminum,
870 g of the solid catalyst obtained above and 260 g of 1-hexene
were added, and the prepolymerization of ethylene was performed at
35.degree. C. for 5 hours to obtain a prepolymerized catalyst
containing 10 g of polyethylene as a prepolymer per 1 g of the
solid catalyst.
Polymerization
In a continuous type fluidized bed gas phase polymerization
apparatus, copolymerization of ethylene and 1-hexene was carried
out at the total pressure of 20 kg/cm.sup.2 -G and a polymerization
temperature of 80.degree. C. To the system were continuously fed
the prepolymerized catalyst prepared above at a feed rate of 0.33
mmol/hr in terms of zirconium atom and triisobutylaluminum at a
feed rate of 10 mmol/hr. Further, to the system were continuously
fed ethylene, 1-hexene, hydrogen and nitrogen to maintain gas
composition constant during the polymerization (gas composition:
1-hexene/ethylene=0.02, hydrogen/ethylene 4.6.times.10.sup.-4,
concentration of ethylene=70%)
The yield of the ethylene/.alpha.-olefin copolymer (A-1) was 60
kg/hr, and this copolymer had a density of 0.926 g/cm.sup.3 and MFR
of 4.2 g/10 min. The temperature at the position of the maximum
peak of an endotherm curve of the copolymer measured by DSO was
117.2.degree. C., the temperature at the position of the peak on
the lowest temperature side was 106.7.degree. C., and the quantity
fraction of the decane-soluble component at room temperature was
0.13 part by weight.
Example 1
The ethylene/.alpha.-olefin copolymer (A-1) was melt kneaded and
pelletized. The resulting pellets were subjected to cast molding to
produce a film having a thickness of 40 .mu.m. The properties of
the copolymer and the film are set forth in Tables 1 and 2.
Examples 2 to 6
Ethylene/.alpha.-olefin copolymers (A-2) to (A-6) were obtained in
the same manner as in the preparation example except that the gas
composition was varied so that the resulting
ethylene/.alpha.-olefin copolymers (A-2) to (A-6) have densities
and MFR shown in Table 1. In the preparation of the
ethylene/.alpha.-olefin copolymer (A-4), however, the
polymerization temperature was varied to 70.degree. C.
The ethylene/.alpha.-olefin copolymers (A-2) to (A-6) were each
melt kneaded and pelletized. The resulting pellets were subjected
to cast molding to produce films each having a thickness of 40
.mu.m. The properties of the copolymers and the films are set forth
in Tables 1 and 2.
TABLE 1 Ethylene/ Comonomer .alpha.-olefin Content Density MFR g/
Value of copolymer Kind (mol %) (g/cm.sup.3) 10 min. MT g Formula
(1) *1 A-1 1-hexene 2.6 0.926 4.2 0.42 0.66 A-2 1-hexene 3.0 0.921
4.0 0.44 0.69 A-3 1-hexene 4.1 0.915 4.0 0.43 0.69 A-4 1-hexene 5.3
0.904 4.3 0.40 0.65 A-5 1-hexene 3.0 0.919 3.1 0.63 0.85 A-6
1-hexene 2.9 0.920 2.1 0.95 1.18 Ethylene/ Quantity fraction of
.alpha.-olefin Value of decane-soluble Value of copolymer FI
S.sup.-1 Formula (2) *2 component (wt %) Formula (3) *3 A-1 260 630
0.13 0.90 A-2 250 600 0.25 1.43 A-3 250 600 0.50 2.52 A-4 260 645
2.10 7.36 A-5 200 465 0.22 1.72 A-6 120 315 0.19 1.56 Ethylene/
Value of Value of Value of TREF .alpha.-olefin Tm.sub.1 Tm Formula
Tm-Tm.sub.1 Formula Formula >100.degree. C. copolymer .degree.
C. .degree. C. (4) *4 .degree. C. (5) *5 (6) *6 Wt %* A-1 106.7
117.2 122.4 10.5 20.4 2.4 5.0 A-2 104.7 115.0 120.4 10.3 23.4 5.4
4.8 A-3 101.0 113.9 118.0 12.9 27.0 9.0 3.5 A-4 90.0 110.2 113.6
20.2 33.6 15.6 1.3 A-5 104.6 114.9 119.6 10.3 24.6 6.6 4.5 A-6
105.0 115.2 120.0 10.2 24.0 6.0 4.0 *1 Formula (1): 2.2 .times.
MFR.sup.-0.84 *2 Formula (2): 150 .times. MFR *3 Formula (3): 80
.times. exp (-100(d - 0.88)) + 0.1 *4 Formula (4): 400 .times. d -
248 *5 Formula (5): 576 - 600d *6 Formula (6): 558 - 600d
*Proportion of the amount of the component which is eluted at a
temperature of not lower than 100.degree. C. in the measurement of
TREF to the total amount of the eluate.
TABLE 2 Complete Film impact Value of heat-sealing Haze Gloss (0.5"
Head) Formula temperature % % (KJ/m) (7) *7 (.degree. C.) Example 1
4.0 105 15.6 12.3 125 Example 2 3.6 102 25.4 22.1 120 Example 3 2.6
105 70.0 44.1 115 Example 4 0.9 109 NB * 157.1 105 Example 5 2.9
105 27.3 27.5 120 Example 6 2.6 106 27.1 24.8 120 Blocking
Elmendorf Force tear Elastic (50.degree. C., strength modulus
Elongation 10 kg, (N/cm) (MPa) (%) 24 hr) MD TD MD TD MD TD (kg/m)
Example 1 780 1180 230 230 670 770 0.11 Example 2 1030 1420 180 180
660 740 0.25 Example 3 1370 1760 140 140 620 650 0.40 Example 4
4700 6620 100 100 640 690 3.0 Example 5 960 1350 180 180 600 730
0.20 Example 6 840 1270 190 190 550 700 0.20 * NB: not broken *7
Formula (7): (-50.17 .times. d) + 47.55
* * * * *